1. Field of the Invention
This invention relates to a rental mat with the prevention of wavy deformation. More specifically, it relates to a rental mat in which wavy phenomenon on the mat surface is repeatedly prevented even when it is used and regenerated over a long period of time.
2. Description of the Prior Art
Heretofore, to prevent indoor entry of outdoor dusts from shoe bottoms, a dust controlling mat has been widely used. This dust-controlling mat is lent to the consumer for a certain period of time, and after being used as spread in a place where people move in and out, it is recovered and regenerated by washing and treated with oiling agent, etc. It is then again lent to the consumer on a rental system.
The rental mats, as disclosed in Japanese Publication No. 7450/84, are a separate-type in which a mat having a pile is detachably applied to a rubber picture framelike base and an integral-type in which a rubber sheet is cemented to the back of a piled mat. The latter tends to be preferred from the viewpoint of an outward appearance.
Binding is strong and, in usual use and washing, the product is not peeled or damaged. But within a relatively short number of rental cycles, waving occurs at the mat surface. This impairs the commercial value of the rental mat and will reduce the walkability and impair the dust removing property of the mat.
In a conventional integral mat, efforts are being made to strengthen the base cloth and the rubber sheet to prevent the peeling of the mat base and the rubber sheet and drop of the piles during long term use. Since the base cloth is very different from the rubber sheet in chemical composition and properties, during production, use and regeneration, a dimensional difference tends to form and this is liable to cause waving. For example, when a rubber sheet is heat-melted to a base cloth of the mat, the rubber sheet is already elongated by heat and the elongation formed by this heat shrinks after production. A dimensional difference forms between the two, and waving occurs between the two. Furthermore, since the rubber is non-shrinkable at the time of washing, the base cloth shrinks to develop a dimensional difference. Thus, likewise, waving also forms. This dimensional difference likewise occurs under conditions in which heat, light, steam or water are used.